Gyratory screen



Dec. 2, 1941. w. J. PARKS GYRATORY SCREEN Filed Sept. 7, 1937 2Sheets-Sheet 1 Dec. 2, 1941. .w. J. PARKS GYRATORY SCREEN Filed Sept. 7,193'? 2 Sheets-Sheet 2 p H. H. .L n

'INVENTOR Va/fer I Part;-

. n WORNQ? Patented Dec. 2,1941

crna'rcnr scanner Walter 1. Parks, Shaker Heights, Ohio ApplicationSeptember 7, 1937, Serial him 162,661 9 cl ims. (01. 209-326) Thepresent invention relates to gyratory mechanism particularly adapted foruse in screening materials and similar operations. The object of theinvention is to provide a system of reciproeating forces which will, bytheir action on the and of the forces generated during the operation ofthe apparatus embodying my invention.

base frame or supporting structure, balance rotating forces generated inthe resilientsupports of a gyrating screen.

Briefly outlined, my invention comprises the provisionof means forbalancing the forces generated by the motion of a gyratory body such asa screen frame, such means consisting essentially of complementarystraight line forces. My invention is particularly adapted to that typeof gyrating screen mechanism wherein the actuating or driving elementconsists of a drive shaft ec-.

centrically journaled. at substantially the center of gravity of aresiliently supported screen frame whereby the latter possesses agyratory motion. I have found that by means of connecting rodseccentrically connected to the drive shaft in a direction opposite tothat of the eccentricity of the screen frame with respect to the center.line of the drive shaft, such connecting rods being angularly disposedwith respect to each other so that their lines of effective action arecomplementary to each other, and that by resiliently supporting both thescreen frame and the connecting rods to the base structure or supportingframe, the forces generated by the gyrating screen body and thecomplementarily disposed connecting rods transmissionv of vibratingforces tothe supporting frame.

To the accomplishment of the foregoing and related ends, said invention,then, consists of the means hereinafter fully described and particularlypointed out in the claims.

The annexed drawings and the following dewill counterbalance each otherto eliminate the scription set forth in detail certain mechanism aembodying the invention, such disclosed means constituting, however, butone of various mechanical forms in which the principle of the invent onmay be used.

said annexed drawings:

Fig. l. is an end elevatlonal view of an apparatus embodying theprinciples of my invention; Fig. 2 is a side elevational view of theapparatus shown in Fig. 1; Fig. 3 is an enlarged detailed sectional viewtaken through the drive shaft assembly; Fig. 4 is a smaller, detailedsectional view of a modified form of construction for the connectingrods and drive shaft; and. Fig. 5 is a diagram illustrative of theprinciple of operation Now referring more particularly to Figs. 1, 2 and3 of the drawings, there is shown therein an apparatus comprising thesupporting member or base frame I upon which the screen frame 2 isresiliently mounted by means of the rubber mounting blocks 3 'and tcured to metal or steel plates which in turn are carried by the frames land 2 respectively. A drive shaft 5 is located substantially at thecenter of gravity of the screen frame 2 and has the eccentric portion 6.

The eccentric portion 5 is journaled in the screen frame 2 by means ofthe bearing 8. The eccentric bushing i, mounted on the shaft 5, isjoumaled in the housing ill by means of the bearing 9. The housing Informs an integral portion of one end of the connecting rod H whose otherend is resiliently connected to the base frame I by means of a rubbermounting block I2.

A second connecting rod i3 is disposed substantially at right; angles tothe connecting rod ii and is connected by means of the hearing" it tothe housing 60. The connecting rod l3 is similarly connected to aresilient rubber mounting on the base frame I, as indicated at IS.

The eccentricities of the eccentric portion 6 and of the bushing l areremoved from each other or are disposed on opposite sides of the centerline of the drive shaft 5. A drive sheave pulley I5 is mounted on theouter end of the drive shaft 5 and adapted to be connected to a primemover such as an electric drive motor (not shown) The center line of thepulley l6 should coincide with the center line of the drive shaft 5.

A counterbalance wheel I! is also mounted on the drive shaft 5. Thewheel II has a fixed eccentric weight 2! and a serrated web l8 for theadjustable radial location of the movable weights IS. The weights 2! andis are preferably so located and adjusted on the counterweight wheel IIthat the center mass of all of the elements connected to the drive shaft5 is made coincident with-the center line of the shaft and midwaybetween the eccentricities of the drive shaft portion 6 and of thebushing I. In such latter case, the

stiffness of the resilient supports l2 and ii for the centricity willhave a proportionately stiffer resillent support than the largereccentricity.

In operation, the screen frame 2 will movewwith a gyratory movementhaving an amplitude equal to twice the eccentricity or distance betweenthe center of the shaft, which has been assumed to he the center ofrotation, and the center of the screen body bearing 8. The housing I0,comprising the ends of the connecting rods II and I3, will also tend togyrate about the center of mass or center line of the drive shaft 5, butdiametrically opposite in instantaneous displacement with respect to thecenter of mass of the screen body or frame 2. The connecting rods II andI3 will not have a gyratory motion throughout their entire lengthinasmuch as their centers of mass are displaced from their point ofeccentric con nection with the drive shaft 5. At some point in thelength of the connecting rods ill and I3 they will have only areciprocating motion along the line through their centers of mass andthe center of their bearing connection to the eccentric portion l. Byproperly proportioning the design of the connecting rods II and I3, thislastmentioned point is made to occur substantially at the location ofthe resilient supports 82 and I5. Accordingly. the effective lines ofaction of the connecting rods II and I3, and of the forces transmittedto and generated in the resilient supports I2 and I5, will be along thelength of such connecting rods. Since each connecting rod I I and I3 isrigid in a direction parallel to its length, but can tilt at rightangles to its length to accommodate the gyratory motion of the housingI0, there will be no lateral displacement transmitted to the resilientlymounted ends of such connecting rods, and they will of course have onlya reciprocating motion in such point of re silient attachment to thebase frame I.

Inasmuch as both connecting rods II and I3 are actuated by the sameeccentric, viz., the eccentric bushing I on the shaft 5, and aredisposed at approximately right angles to each other, they will have acomplementary reciprocating motion. That is to say, when one of theresilient supports I2 or I5 is at its maximum displacement and exertingits maximum force on the base frame, the other resilient support willhave no relative displacement and will exert no additional force on thebase frame. The vector sum of the displacements exerted upon theresilient supports l2 and I5 will therefore be at all times equal, sincethe amount of the force on one support is varying from zero to maximumwhile the force on the other support is varying fromvmaximum to zero.And as will be presently pointed out, the forces transmitted to orgenerated in the resilient supports l2 and I5 counterbalance the forceswhich are transmitted to and generated in the resilient supports 3 and 4by reason of the gyratory motion of the screen body or frame 2.

Referring to Fig. 5, the motions and forces of the respective movingelements of the abovedescribed apparatus are diagrammaticallyillustrated upon a pair of coordinates l0! and YY which intersect at thecenter of mass of the system. The gyratory path of travel of the screenbody moves about this center of mass and at a radius substantially equalto the diametrically oppositely disposed point of connection of theconnecting rods which are designated as I and 2. The instantaneousdisplacement of the screen body is represented by the displacement ofany point in its path of travel on the X and Y axes. Since theconnecting rods I and 2 are disposed at right angles to each other, andtheir effective and respective displacements are along their lengthsonly, it will be seen, for the purpose of the diagrammatic illustration,that the connecting rod I can have an effective displacement only alongthe X axis, and the connecting rod 2 can have an efl'ective displacementalong the Y axis. Since the eccentricities of the points of connectlonof the screen body and of the connecting rods I and 2 are removed fromeach other with respect to the center of mass, it will be seen that therespective effective displacement forces of the screen body and of theconnecting rods are also 180 removed from each other, and thus while thescreen body is moving through the first quadrant, the points ofeffective displacement of the connecting rods will be moving through thethird quadrant of the diagram. The variation, amount and direction ofthe eflective forces of the screen body and of the connecting rods areanalyzed in the following table which for the purpose of convenience inillustration is divided according to the four quadrants of the diagram.

The direction of motion of the forces with respectto the X and Y axes isdenoted by the customary plus and minus signs.

Amount of forces Direction of forces QumL rant X axis Y axis X axis Yaxis Screen bodyml. 0 to max" Maictoi) 1 Connecting rod .do 0 i T) 3Cgnnccting rod 0 Mnx.to0. 0 3

Screen body-. Max. toO. 0 to max 2 Connecting rod .do l l l. O 4Cgnnccting rod 0 0 to max 0 4 Screen body. 0 to max. Max. toO 3Connecting rod ...do 0 1 Cgnnecting rod 0 Max.to0. 0 1

Screen body Max. m0 0 to max-. 4 Connecting rod ...do 0 2 Cgnnccting rod0 0 to max.. 0 2

Referring to the above table of analysis. it will thus be seen. that theinstantaneous forces generated in the resilient supports of the screenbody are equal in amount and opposite in direction to the instantaneousforces generated through the connecting rods and their resilientsupports, so that there is a counterbalancing at all times of the forcestransmitted to the supporting frame.

Referring again to Fig. 5, the above statement is substantiated by thefollowing analysis:

Assuming that the screen body is in a point of its pathof travel asindicated in the first quadrant, then the vector components of thispoint will be represented by the values which it subtends on the X and Yaxes, such components being represented as X1 and Y1, respectively. Atthe same time, the effective point of connection of the connecting rodsI and 2 is located 180 from the instantaneous point of travel of thescreen body and in the third quadrant. Since the effective displacementand direction of the forces. of the connecting rods I and 2 arein astraight line only, each one of the connecting rods will have aneifective displacement along only one of the two coordinate axes. Thus,at the assumed instantaneous point, the connecting rod I will have aneffective displacement as represented by the value -X1 and theconnecting the drive shaft, Referring more particularly to this latterfigure, the drive shaft has an eccentric bushing 2| upon which theconnecting rods 22 and 23 are mounted side by side by means of thebearings 24 and 25 respectively. The lower ends of the connecting rods22 and 23 are resiliently connected to opposite sides of the channel ofthe base frame I by means of rubber mounting blocks such as indicated at26.

Qther modes of applying the principle of my invention may be employedinstead of the one explained, change being made as regards the mechanismherein disclosed, provided the-means stated by any of the followingclaims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a gyrating screen mechanism, the combination of a supportingmember, a screen frame resiliently supported on said member, a driveshaft having eccentric means thereon, and individual connecting rodshaving one end rotatably connected to said eccentric means and the otherend being connected to said supporting member, said connecting rodsbeing disposed at right angles to each other.

2. In a gyrating screen mechanism, the combination of a supportingmember, a screen frame resiliently supported on said member, a driveshaft having eccentric means thereon, and individual connecting rodshaving one end rotatably connected to said eccentric means and the otherend being connected to said supporting member, said connecting rodsbeing disposed at right angles to each other, and resilient meansconnecting said connecting rods to said supporting member.

3. In a gyrating screen mechanism, the combination of a supportingmember, a screen frame resiliently supported on said member, a driveshaft having oppositely disposed eccentrics thereon, one of saideccentrics being connected to said screen frame, and individualconnecting rods disposed at right angles to each other, one end of saidconnecting rods being rotatably connected to the other of saideccentrics'and the other end of said connecting rods being connected tosaid supporting member.

4. In a gyrating screen mechanism, the combination of a supportingmember, a screen frame resiliently supported on said member, a driveshaft having oppositely disposed eccentrics thereon, one of saideccentrics being connected to said screen frame, and individualconnecting rods disposed at right angles to each other, one end of saidconnecting rods being rotatably connected to the other of saideccentrics and the other end of said connecting rods being connected tosaid supporting member, and resilient means for connecting saidconnecting rods to said supporting mem-.

her.

5. In a gyrating screen mechanism, a supporting member, a screen bodyresiliently supported on said member, a drive shaft having portions Ieccentric with respect to each other and each eccentric to a centre ofrotation lying between the centers of said eccentric portions, means forconnecting said screen body to one of said eccentric portions, companionbalancing bodies disposed at one side of said screen body, meansconnecting one end of each of said balancing bodies to the other of saideccentric portions, and resilient supports for said balancing bodiesmounted on said supporting member and located at points spaced from saidconnection of said balancing bodies to said, shaft.

6. In a gyrating mechanism, the combination of a supporting member, agyratory screen frame resiliently supported on said member, a driveshaft having oppositely disposed eccentric means, one of said eccentricmeans being connected to said screen frame, connecting rods each havingone end resiliently connected to said supporting member and the otherend connected to the other of said eccentric means, said connecting rodsso disposed relatively to each other as to create complementarybalancing forces at right angles to'each other, the vector sum of whichbalances the forces generated in the resilient supports of said screenframe as a result of its gyratory motion.

7. In a gyrating screen mechanism,'the combination of a resilientlysupported gyratory screen body, a drive shafthaving eccentric meansthereon, and means comprising resilient supports and companion bodiesfor balancing the forces generated in the resilient supports of saidgyratory body with only straight line forces generated in the resilientsupports of said companion bodies, said bodies each having one endrotatably connected to said eccentric means and the other end connectedto said resilient supports, said companion bodies being disposed at oneside of said screen body and angularly movable with respect to eachother and having an instantaneous displacement opposite to that of saidgyratory screen body.

8. In a gyrating screen mechanism, the combination of a supportingmember, a screen frame resiliently supported on said member, a driveshaft having oppositely disposed eccentrics thereon, one of saideccentrics being connected to said. screen frame, and connecting rodsdisposed at an angle of less than with respect to each other, one end ofsaid connecting rods being rotatably connected to the other of saideccentrics and the other end of said connect-' ing rods being connectedto said supporting -member, and resilient means for connecting saidconnecting rods to said supporting member.

WALTER J. PARKS.

